1. Field of the Invention
The present invention relates to a detection apparatus, and more particularly to a detection apparatus set up in a cleaning tank, and is adjustable according to the size thereof.
2. Description of the Related Art
A complete semiconductor process includes many steps such as film deposition, lithography, and etching. Large quantities of materials and solutions are used for manufacturing or washing, while mostly water is used in a wet bench.
Acidic or chemical solvents such as H2SO4, HF and H3PO4 are the principal solutions used in etching or dissolving in semiconductor processes. Residue of acidic or chemical solvents easily remains on the wafer, which must then be thoroughly cleaned with large quantities of deionized water (DI water).
The chemical wet bench includes a cleaning tank, a cassette, and a megasonic device.
In FIG. 1, wafers 101 are vertically disposed in the cassette 102. The two wafers 101 are separated by a divider 102a. The wafers 101 are supported in an upright position by the divider 102a. 
In FIG. 2, the cassette 102 and the wafers 101 are placed in a cleaning tank 105. The cleaning tank 105 has a bottom portion 104 provided with air holes 104a. 
A megasonic device 106 comprises a megasonic tank 106a. Cleaning solution 107 is placed in the megasonic tank 106a. The megasonic device 106 is coupled beneath the cleaning tank 105.
The cleaning solution 107, at megasonic energy levels, is injected into the cleaning tank 105 through the air holes 104a of the bottom portion 104.
FIG. 3 shows a cleaning tank 105, in which the cassette 102 is placed and a megasonic device 106, which includes megasonic tank 106a containing DI water 107, coupled beneath the cleaning tank 105.
The DI water 107, at megasonic energy levels, is injected from megasonic tank 106a into the cleaning tank 105 via the air holes of the bottom portion 104 when the megasonic device 106 is turned on.
The cleaning tank 105 contains DI water 107 and the wafers 101. The cleaning tank 105 further comprises a discharging portion (not shown). Surplus DI water 107 is discharged by the discharging portion. Residue on the wafers 101 cannot be thoroughly removed if the megasonic device 106 provides insufficient megasonic energy due to damage.
There are several commercially available detectors to measure the megasonic energy levels of the DI water 107 in the cleaning tank 105. The detector is placed in the activated cleaning tank 105 in a predetermined position, and the megasonic energy levels of the DI water 107 in the cleaning tank 105 are directly measured by the detector. The detector can be, for example, a sound level meter.
Because commercially available detectors require manual operation and estimation of distance by the operator, error can result.